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ILLINOIS 
COAL  MINING  INVESTIGATIONS 

CO-OPERATIVE  AGREEMENT 

State  Geological  Survey 

Department  of  Mining  Engineering,  University  of  Illinois 

U.  S.  Bureau  of  Mines. 


BULLETIN  2 


M 


Coal  Mining  Practice    / 

IN 

District  VIII  (Danville) 


BY 

S.  O.  ANDROS 
Field  Work  by  R.  Y.  Williams  and  S.  O.  Andros 


ILLINOIS 

COAL  MINING  INVESTIGATIONS 

URBANA 

1914 


The  Forty-seventh  General  Assembly  of  the  State  of  Illinois,  with 
a  view  of  conserving  the  lives  of  the  mine  workers  and  the  mineral 
resources  of  the  State,  authorized  an  investigation  of  the  coal  resources 
and  mining  practices  of  Illinois  by  the  Department  of  Mining  Engineer- 
ing of  the  University  of  Illinois  and  the  State  Geological  Survey  in 
co-operation  with  the  United  States  Bureau  of  Mines.  A  co-operative 
agreement  was  approved  by  the  Secretary  of  the  Interior  and  by  repre- 
sentatives of  the  State  of  Illinois. 

The  direction  of  this  investigation  is  vested  in  the  Director  of  the 
United  States  Bureau  of  Mines,  the  Director  of  the  State  Geological 
Survey,  and  the  Head  of  the  Department  of  Mining  Engineering,  Uni- 
versity of  Illinois,  who  jointly  determine  the  methods  to  be  employed 
in  the  conduct  of  the  work  and  exercise  general  editorial  supervision 
over  the  publication  of  the  results,  but  each  party  to  the  agreement 
directs  the  work  of  its  agents  in  carrying  on  the  investigation  thus 
mutually  agreed  on. 

The  reports  of  the  investigation  are  issued  in  the  form  of  bulletins, 
either  by  the  State  Geological  Survey*,  the  Department  of  Mining 
Engineering,  University  of  Illinois,  or  the  United  States  Bureau  of 
Mines.  For  copies  of  the  bulletins  issued  by  the  State  and  for  informa- 
tion about  the  work,  address  Coal  Mining  Investigations,  University  of 
Illinois,  Urbana,  111.  For  bulletins  issued  by  the  United  States  Bureau 
of  Mines,  address  Director,  United  States  Bureau  of  Mines,  Washington, 
D.C. 


3  3051  00006  3804 


ILLINOIS 
COAL  MINING  INVESTIGATIONS 

CO-OPERATIVE  AGREEMENT 


State  Geological  Survey 

Department  of  Mining  Engineering,  University  of  Illinois 

U.  S.  Bureau  of  Mines. 


BULLETIN   2 


Coal  Mining  Practice 


IN 


District   VIII  (Danville) 


BY 

S.  O.  ANDROS 
Field  Work  by  R.  Y.  Williams  and  S.  O.  Andros 


ILLINOIS 

COAL  MINING  INVESTIGATIONS 

URBANA 

1914 


Springfield,  III. 

Illinois  State  Journal  Co.,  State  Printers 

19  14 


CONTENTS 


PAGE 

Introduction 7 

History 9 

Description  of  coal  beds 12 

Mining  practice 14 

Room-and-pillar  system 15 

Method  of  working 15 

Ventilation 22 

Blasting 26 

Timbering 28 

Haulage 34 

Hoisting 36 

Preparation  of  coal 39 

Stripping 44 


ILLUSTRATIONS 


No.  PAGE 

1.  Map  showing  area  of  District  VIII Frontispiece 

2.  Typical  surface  plant  of  a  shaft-mine 10 

3.  Slope  lined  with  concrete 14 

4.  Portal  of  a  drift  mine 15 

5.  Plan  of  typical  mine 16 

6.  Surface  subsidence  near  Westville 17 

7.  Tongue-and-groove  lining  of  overcast 18 

8.  Customary  method  of  placing  shots  in  undercut  face 19 

9.  Sketch  of  three-piece  gangway  sets 21 

10.  Timbering  in  haulage  entry 24 

11.  Destruction  of  timber  by  crushing 26 

12.  Roof-fall  in  room 27 

13.  Roof-fall  in  entry 27 

14.  Method  of  propping  near  face  of  room 29 

15.  Plan  of  room  showing  propping 30 

16.  Steel  I-beams  and  brick  pillars  at  bottom 31 

17.  Inby  end  of  concrete-lined  bottom 31 

18.  Concrete  and  steel-I-beam  in  slope  bottom 32 

19.  Typical  caging-place  at  shaft-bottom 34 

20.  Abandoned  drag-line  excavator 35 

21.  Island  of  overburden  at  stripping  mine 36 

22.  Removing  top-soil  with  hydraulic  monitors 37 

23.  Shale  and  top-soil  overlying  coal 38 

24.  Steam-shovel  digging  shale  overburden 39 

25.  Drilling  hole  for  blasting  at  stripping-mine 40 

26.  Dinky  locomotive  and  haulage-way  at  stripping  mine 41 

27.  Stripping-mine  haulage-way 41 

28.  Stripping-mine  thorough-cut 42 

29.  Stripping-mine  coal  face 43 

30.  Stripping-mine  spoil-bank 44 

31.  Steam-shovel  with  belt-conveyor  spoil-elevator 45 

32.  Section  of  bed  No.  7 46 


TABLES 


No.  PAGE 

1.  Statistics  for  District  VIII  in  1912 7 

2.  Comparative  analyses  of  seams  6  and  7 , 13 

3.  Physical  characteristics  of  mines IS 

4.  Percentage  of  coal  extracted  from  seam 18 

5.  Relation  between  accidents,  number  of  employees  and  tonnage 20 

6.  Causes  of  accidents  in  State  and  District  VIII,  1912 20 

7.  Per  capita  production  of  employees 22 

8.  Data  on  ventilating  equipment 23 

9.  Pressures  developed  in  explosibility  apparatus 23 

10.  Hunidity  data  for  District  VIII 2* 

11.  Method  and  frequency  of  humid ification 25 

12.  Cost  and  material  of  efficient  stoppings 25 

13.  Blasting  practice 28 

14.  Data  concerning  props  in  rooms 33 

15.  Haulage  items 3b 

16.  Equipment  for  hoisting 38 

17.  Tipple  equipment 42 

18.  Surface  equipment 42 


Fig.  1.    Map  showing  by  cross-hatching  the  area  of  District  VIII 


INTRODUCTION 


COAL  MINING  PRACTICE  IN   DISTRICT  VIII 
(DANVILLE) 

By  S.   O.   ANDROS 
Field  Work  by  R.  Y.  Williams  and  S.  O.  Andros 

INTRODUCTION 

The  Danville  district,  including  Vermilion  and  Edgar  counties,  as 
shown  in  Fig.  1,  is  District  VIII  of  the  Illinois  Coal  Mining  Investi- 
gations. It  contains  mines  working  in  beds  6  and  7  of  the  Illinois  State 
Geological  Survey  correlation. 

A  detailed  description  of  the  districts  into  which  the  State  has 
been  divided  and  the  method  of  collecting  the  data  upon  which  this 
bulletin  is  based  is  contained  in  Bulletin  1,  "A  Preliminary  Keport  on 
Organization  and  Method." 

Vermilion  County  at  present  ranks  eighth  among  the  fifty-two  coal 
producing  counties  of  the  State,  its  total  output  for  the  year  ending 
June  30,  1912,  being  3,374,443  tons,  which  amount  is  5.8  per  cent  of 
the  total  output  of  the  State.  Of  this  amount  20.2  per  cent,  683,789 
tons,  were  mined  by  machines.  The  total  tonnage  was  produced  by 
forty-nine  mines  with  4,007  employees,  or  5.0  per  cent  of  the  total 
employees  of  the  coal  mining  industry  in  Illinois.  Of  these  forty-nine 
mines,  eighteen  were  shipping  and  thirty-one  local. 

Edgar  County  produced  a  small  amount  of  coal  in  1911,  but  ceased 
production  during  that  year  and  in  1912  was  not  a  contributor  to  the 
production  of  the  district. 

Table  1 — Statistics  for  District  17 If  for  (he  Year  Ending 
June  SO,  1912* 


District 
Vin  otate 

(all  mines)    !    (all  mines) 


Per  cent 

of 
district 


Total  production 

Average  daily  tonnage 

Number  tons  mined  by  machines 

Average  days  of  active  operation 

Number  days  of  work  performed  in  1912 

Total  employees 

Number  surface  employees 

Number  underground  employees 

Number  underground  employees  per  each  surface  employee 

Number  tons  mined  per  day  per  employee 

Number  tons  mined  per  day  per  surface  employee 

Number  tons  mined  per  day  per  underground  employee. . . 
Number  fatal  accidents 

Per  cent  from  falling  coal  or  rock 

Per  cent  from  pit  cars. 

Per  cent  from  explosives 

Number  deaths  per  1,000  employees. 

Number  tons  mined  to  each  life  lost 

Number  non-fatal  accidents 

Percent  from  falling  coal  or  rock 

Per  cent  from  pit  cars 

Per  cent  from  explosives 

Number  injuries  per  1 ,000  employees 

Number  tons  mined  to  each  man  injured 


,374,  143 

18,339 

683,  789 

IM 

737,  288 

J,  007 

305 

3,702 

12.2 

4.6 

60.  1 

1.9 

is 


59 

47. :» 

27.  1 

5.  I 

14.7 

r,  194 


11-', 


57,514,240 

359,  464 

25,550  019 

160 

705,  760 

70,  1 1  I 

7,049 

72,  362 

11.3 

4.5 

50.9 

1.9 

180 

54.  I 

is.  8 

7.2 

2.  3 

319,524 

800 

45.  5 

26.  3 

2.0 

10.1 

71,893 


5.8 


5.0 
4.3 
5.1 


10.0 


Compiled  from  Thirty-flrsl  Annual  Coal  Keport  of  I  Hindis. 


8  COAL    MINING    INVESTIGATIONS 

Table  1  gives  comparative  statistics  for  the  district  and  for  the 
State  for  the  year  ending  June  30,  1912. 

Acknowledgments  are  due  to  the  operators  of  the  district  who 
offered  every  facility  for  study  of  the  mines  and  to  the  superintendents 
and  mine  managers  who  accompanied  the  engineers  through  the  under- 
ground workings.  Valuable  assistance  was  rendered  by  Mr.  Thomas 
Moses,  and  Mr.  W.  S.  Burris,  superintendents  of  the  Bunsen  Coal 
Company  in  reviewing  the  manuscript  of  this  bulletin. 


HISTORY 


HISTORY 


Mining  on  a  commercial  scale  began  in  1866  when  Win.  Kirkland 
and  Hugh  Blankeney  and  Mr.  Graves  opened  a  stripping  mine  on  Grape 
Creek.  In  1810  considerable  work  was  done  at  the  West  Vermilion 
Heights  shaft,  and  through  the  early  seventies  the  Grape  Creek  Coal 
Company  opened  np  what  are  now  known  as  the  Old  Grape  Creek  mines, 
about  four  miles  southeast  of  Danville,  midway  between  Danville  and 
Westville  on  the  line  of  the  C.  &  E.  I.  E.  E.  This  company  went  into 
the  hands  of  a  receiver  in  1893  and  its  mines  were  foreclosed  to  the 
Eastern  Illinois  Coal  Company,  which  leased  its  holdings  to  the  Brook- 
side  Coal  Company.  Until  1892  it  was  not  supposed  that  the  Grape 
Creek  or  No.  6  bed  extended  under  the  prairie  west  of  Danville  and 
the  first  shaft  in  that  territory  was  sunk  by  Michael  Kelley  in  that 
year.  This  mine  was  known  as  Kelley  Xo.  2,  Mr.  Kelley  having 
previously  sunk  a  shaft,  Kelley  Xo.  1,  about  five  miles  south  and  one 
mile  east  of  Danville.  In  1895  the  Westville  Coal  Company  sunk  the 
Westville  Xo.  1  shaft,  which  at  that  time  was  the  opening  farthest  west 
and  south  in  the  Xo.  6  bed.  This  mine  was  rapidly  developed  by  elec- 
tric mining-machines  and  in  L898  was  producing  2,000  tons  of  coal 
in  eight  hours  of  hoisting.  This  is  supposed  to  be  the  first  mine  in 
Illinois  to  produce  so  large  an  amount  of  coal  in  an  eight-hour  shift. 
The  Catlin  mine,  sunk  in  1895  by  A.  C.  Daniels,  was  sold  to  Jones  and 
Adams,  who,  in  turn,  sold  it  to  the  Chicago  Collieries  Company.  It  is 
now  being  operated  by  the  Danville  Colleries  Company  in  the  Danville 
or  Xo.  7  bed.  This  is  the  only  mine  in  the  district  where  beds  6  and  7 
were  both  operated   from  the  same  shaft. 

After  1895,  mines  of  large  production  followed  very  rapidly.  The 
first  self-dumping  cage  in  the  district  was  installed  at  the  Pawnee  mine 
in  1898.  The  Kelley  Coal  Company  in  L896  sank  the  Kelley  No.  3 
shaft,  located  one-half  mile  west  of  Westville.  and  in  1901  this  mine 
produced  the  largest  amount  of  coal  of  any  mine  in  the  Danville  district. 
In  the  same  year  the  Brookside  Coal  Company  operated  the  Brookside 
No.  1,  a  shaft  mine  on  the  C.  &  E.  I.  R.  1...  one  and  one-half  miles  from 
Westville  Station.  This  company  also  opened  a  small  drift  mine, 
Brookside  Xo.  2,  located  one  and  one-half  miles  east  of  No.  1. 

In  1899  the  1 1  i in  rod  Coal  Company  sank  the  Himrod  shaft  and 
established  the  town  of  Himrod.  The  mine  was  equipped  with  mining- 
machines  operated  by  compressed  air,  but  was  abandoned  in  1907.  In 
1902  the  Kelley  Coal  Company  opened  its  No.  I  mine.  In  1903  the 
Westville  Coal  Company  sank  its  No.  2  -haft  and  in  the  same  year  the 
Electric  Coal  Company.  W.  C.  Hartshorn,  President,  opened  the  Electric 
mine  four  and  one-half  miles  west  of  Danville.  In  1!»<»i  the  Westville 
— 2  G  2 


10 


HISTORY  11 

Coal  Company  sank  the  No.  3  and  No.  4  shafts  at  Westville,  the  No.  4 
mine  being  now  (1913)  the  most  westerly  mine  in  operation  in  the 
district.  The  mines  of  the  Westville  Coal  Company  were  taken  over  in 
1905  by  the  Dering  Coal  Company. 

The  Little  Vermilion  shaft  was  sunk  in  1905,  about  one  and  one- 
half  miles  north  of  Georgetown.  In  that  year  the  properties  of  the 
Himrod  Coal  Company  and  the  Kelley  Coal  Company  were  consolidated 
by  the  Illinois  Traction  System  and  in  1907  were  sold  to  Mr.  E.  R. 
Hammond,  who  sold  them  in  1909  to  the  Bunsen  Coal  Company. 

The  Fairmount  mine  was  opened  by  the  Fairmount  Coal  Company 
in  1907  at  Bennett  Station,  ten  miles  southeast  of  Danville. 

A  stripping  mine  at  Missionfield,  six  miles  west  of  Danville,  was 
operated  under  a  lease  given  by  the  Consolidated  Coal  Company,  till  its 
abandonment  in  1900.  Operations  were  again  begun  on  this  tract  in 
December,  1909,  by  the  Missionfield  Coal  Company.  This  company  at 
first  used  the  drag-line  shovel  in  removing  the  overburden,  but  in  1910 
purchased  a  revolving  shovel  which,  at  the  time  of  the  purchase,  was 
the  largest  revolving  steam-shovel  in  the  world.  The  old  salt-wells  of 
an  early  period  were  located  about  100  feet  from  the  present  tipple  of 
this  company,  and  it  was  from  these  salt-wells  that  the  Salt  Fork  Eiver 
derived  its  name. 

Stripping  operations  were  begun  by  the  Western  Brick  Company 
in  1902  on  land  located  two  miles  west  of  Danville  where  formerly  there 
had  been  a  room-and-pillar  mine,  and  this  company  still  operates  a 
portion  of  its  property  on  the  room-and-pillar  system.  From  the  shale 
overlying  the  coal,  this  company  has  an  annual  output  of  eighty-five 
million  brick. 


12  COAL   MINING   INVESTIGATIONS 


DESCRIPTION  OF  COAL  BEDS 


In  this  district  all  the  large  outputs  are  produced  from  the  No.  6 
bed  of  the  Illinois  State  Geological  Survey  correlation. 

The  chief  characteristic  of  the  No.  6  bed  which  averages  6  feet  in 
thickness,  is  the  presence  of  a  blue-band  which  divides  it  into  upper 
and  lower  benches.  This  blue-band  varies  from  soft  dust  to  hard  gray 
shale  and  occurs  about  2  feet  above  the  floor.  In  addition  to  this  blue- 
baud  there  are  several  shale  and  sulphur-bands  of  variable  horizontal 
and  vertical  extent. 

The  roof  over  coal  No.  6  is  variable.  Near  Danville  the  immediate 
roof  is  a  grayish  black  shale  about  6  feet  thick.  This  shale,  lying 
between  the  coal  and  the  cap-rock  of  dark  gray  nodular  limestone  makes 
an  easily  supported  roof.  In  the  vicinity  of  Westville  and  Georgetown, 
the  immediate  roof  is  usually  a  gray  shale  which  shows  no  distinct 
bedding,  has  little  cohesion,  falls  in  conchoidal  masses,  and  is  extremely 
difficult  to  support.  Further,  stringers  of  coal  extend  from  the  bed 
proper  into  the  roof  material  and  render  the  roof  more  difficult  of  sup- 
port. In  isolated  cases  there  are  3  to  4  inches  of  black  shale  between 
the  coal  and  the  gray  shale  which  forms  the  cap-rock.  Whenever  this 
black  shale  is  broken,  air  and  moisture  disintegrate  the  gray  shale  cap- 
rock  and  the  roof  becomes  insupportable. 

In  all  parts  of  the  Danville  district  the  floor  is  a  soft  fireclay. 

The  No.  7  bed  varies  in  thickness  from  2y2  to  5%  feet  and  averages 
5  feet.  The  coal  has  two  benches  separated  by  a  clay-band  1  inch  thick, 
which  persists  through  the  bed  from  6  to  8  inches  above  the  floor.  The 
two  benches  present  no  great  difference  in  appearance  or  in  physical 
character  except  locally  where  the  top  bench  is  harder  and  has  a  brighter 
luster.  The  No.  7  bed  generally  has  slightly  more  impurities  than  the 
No.  6  bed,  higher  volatile  matter,  lower  fixed  carbon,  and  higher  sulphur 
content  as  shown  by  Table  2,  obtained  from  analyses  of  thirty-one  face 
samples  in  No.  6  and  of  eighteen  face  samples  in  No.  7.  A  detailed 
discussion  of  these  analyses  will  be  given  in  a  later  bulletin.  The  bands 
of  pyrites  occur  persistently  at  a  height  of  20  to  26  inches  above  the 
floor  and  "sulphur  balls"  or  nodular  concretions  of  pyrites  are  present 
in  such  quantity  as  to  make  profitable  their  separation  from  the  coal 
by  hand  picking  in  the  mine  and  by  a  further  separation  on  the  surface 
in  rotating  cylinders. 

In  both  beds  in  the  district  there  are  numerous  rolls,  called  "faults," 
or  "horsebacks"  by  the  miners.  These  rolls  appear  to  have  been  due  to 
unequal  settling  of  the  coaly  matter  and  the  necessary  readjustment  of 
the  roof  materials,  during  the  formation  of  the  coal.  In  many  cases  the 
roll  entirely  displaces  the  coal. 


DESCRIPTION    OF    COAL    BEDS 


13 


The  mines  in  District  VIII  are  shallow  and  the  deepest  mine  does 
not  exceed  300  feet.  A  detailed  and  comprehensive  report  on  the  geology 
of  this  district  is  in  preparation  and  will  be  published  later  as  a  separate 
bulletin. 


Table    2 — Comparative    Analyses    of   Beds   Six   and    Seven   Made    by 

Prof.  S.  W.  Parr- 


Coal  moisture  free 

Moisture 

B.  t.  u. 

Bed 

Volatile 
matter 

Fixed 
carbon 

Ash 

Sulphur 

Moisture 
free 

Unit 
coal 

Six 

41.94 
44.01 

47.14 
44.  53 

10.92 

11.47 

2.98 
3.37 

14.  45         12.  764 

14,  575 

Seven 

12.99 

12, 807 

14,  740 

*  Number  of  analyses  averaged,  coal  No.  6,  31;  coal  No.  7.  18. 


14 


COAL    MINING    INVESTIGATIONS 


MINING  PRACTICE 


In  the  Danville  district  the  beds  lie  at  varying  depths  below  the 
surface  and  various  means  of  reaching  the  coal  are  employed.  At 
eighteen  of  the  forty-nine  mines  in  the  district  the  coal  is  reached  by  a 


Slope  lined  with  concrete 


shaft;  at  seventeen  by  a  drift;  at  ten  by  a  slope;  and  at  four  the  coal  is 
exposed  by  removing  the  overburden  with  a  steam-shovel.  At  one  prop- 
erty, where  the  surface  exhibits  considerable  relief,  No.  7  is  being  worked 
through  a  slope  and  by  a  drift  and  a  large  area  is  also  being  stripped. 


MINING    PEACTICE 

ROOM-AND-PILLAR  SYSTEM 


15 


METHOD  OF   WORKING 

Mining  in  the  district  was  begun  before  the  refinements  of  method 
necessitated  by  the  present  keen  competition  in  the  industry  were  known. 
Much  progress  has  been  made  in  efficiency  and  safety  of  mining  in 
several  mines  but  there  still  exists  many  examples  of  "gopher-mining" 
which  are  typical  of  the  inefficient  and  unsafe  methods  of  an  earlier 
period.  Six  of  the  eighteen  shipping  mines  of  the  district  were  examined 
and  the  ages  of  these  mines  varied  from  five  to  nine  years. 


Fig  4.     Portal  of  a  drift  mine 


Those  mines  in  the  district  which  are  now  producing  the  greatest 
daily  tonnage  were  not  opened  by  the  present  operators  but  were  pro- 
jected by  former  owners  when  the  comparatively  small  outputs  did  not 
demand  rapid  and  uninterrupted  haulage  and  hoisting.  Even  had  the 
original  projections  been  made  according  to  a  modern  system,  if  would 
have  been  impossible  to  adhere  to  them  on  account  of  the  many  rolls  in 
the  roof  which  cause  a  deviation  from  an  outlined  system.     Whether  the 


16 


COAL    MINING    INVESTIGATIONS 


bed  is  reached  by  a  shaft,  Fig.  2,  a  slope,  Fig.  3,  or  a  drift,  Fig.  4,  the 
system  of  mining  generally  adopted  in  the  district  is  the  simplest  form 
of  donble-entry  room-and-pillar  working.  In  each  mine  examined  a 
main  entry  is  driven  towards  the  property  lines  from  each  side  of  the 
hoisting-shaft,  paralleled  by  an  air-conrse  driven  from  the  air-shaft. 
Along  the  main  entry  pairs  of  cross-entries  are  driven  at  a  right  angle 
from  both  sides  of  the  main  entrv  at  intervals  of  300  to  500  feet.   Booms 


Plan  of  typical  mine 


are  turned  at  a  right  angle  from  each  entry  of  a  pair  of  cross-entries. 
The  roof  is  usually  so  difficult  to  support  that  both  main  and  cross- 
entries  are  very  narrow  and  room-necks  are  driven  narrow  and  long  to 
provide  a  large  room-stub. 

The  frequent  occurrence  of  rolls  has  a  marked  effect  on  the  manner 
of  driving  rooms.     In  a  roll  area  it  is  difficult  to  support  the  roof  and 


MINING    PRACTICE 


17 


the  expense  of  driving  through  the  hard  rock  of  the  roll  is  great.  Con- 
sequently, as  shown  in  Fig.  5,  which  is  the  map  of  a  mine  typical  of  the 
district,  when  a  roll  is  encountered  in  driving  rooms  it  is  customary  to 
change  the  direction  of  the  room  and  to  drive  it  parallel  to  the  roll 
until  the  coal  resumes  its  normal  condition.  Often  it  is  necessary  to 
abandon  a  room  before  it  has  been  driven  its  proper  length.  As  the 
rolls  are  of  frequent  occurrence,  the  amount  of  coal  that  will  be  gained 
in  any  section  of  the  mine  is  problematical.  Consequently,  the  operator, 
on  reaching  that  portion  of  the  coal  where  the  seam  regains  its  normal 
thickness  will  attempt  to  get  as  much  of  the  coal  in  the  seam  as  possible 
during  the  first  working.  Little  attempt  is  made  to  preserve  a  constant 
room-pillar  width  and  the  practice  of  gouging  pillars  is  common  in  the 
smaller  mines.  No  systematic  pillar  drawing  is  attempted  because  with 
present  practice  there  is  but  little  pillar  left  to  draw  when  the  rooms 


Fig.  6.    Surface  subsidence  near  Westville 


are  driven  up  to  their  full  length.  The  roof  is  so  treacherous,  especially 
in  the  vicinity  of  the  rolls  that  it  is  not  safe  to  leave  wide  spans  of  roof 
unsupported  by  pillars.  The  width  of  room-pillars  at  the  mines  examined 
varied  from  4  to  1(5  feet  and  room-widths  from  21  to  43  feet.  Table  3 
gives  dimensions  of  workings  at  each  mine  examined.  It  will  be  noticed 
in  this  table  that  narrow  room-pillars  were  found  in  Mine  No.  91,  where 
the  following  dimensions  were  measured  : 

Eoom  centers,  47  feet. 

Room  widths,  43  feet. 

Room-pillar  width,  4  feet. 

Although  pillar-gouging  in  the  district  has  resulted 
centage  of  extraction  from  the  bed  in  the  first  working, 
a  subsequent  loss  of  coal  through  squeezes  due  to  narrow  pillars.     The 

mines  examined   is  70  per  cent.     Table  4 


n  a  high  per- 
it  has  caused 


average  extraction  for  the  six 


—3  G  2 


18 


COAL    MINING    INVESTIGATIONS 


gives  the  per  cent  of  bed  extracted  at  each  mine.  These  percentages 
were  calculated  from  measurements  made  in  the  mine  and  were  checked 
by  figures  of  production  per  acre  obtained  from  the  books  of  each  oper- 
ating company  and  by  planimeter  measurements  of  mine  maps. 


Table  3 — Physical  Characteristics  of  Mines 


CE 

o 

1 

"3 

o 

P 

Pillar  widths  in  feet 

Entry 
widths  in 

Rooms 
in  feet 

Roo 

m — 

en 
O     . 

h 

"5 

g 
3 

O 

o 

.as 

3 

£ 
o 
o 
PC 

feet 

Number  mine 

en 

O 

Length 
Width 

1 

% 

CO"-1 

Ninety-one 

Ninety-two 

Ninety-three 

Ninety -four 

Ninety-five 

Ninety-seven 

6 
6 
6 

6 

217 
240 
186 
90 
90 
223 

25 
35 
21 
16 

21 
30 
21 
12 

40 
60 
50 
17 

4 

3 
16 

6 
11 

9 

9 

8 

6 

9 

9 
6 
6 

8 

200  43 
240  24 
200  1  24 
240  24 
500  25 
150         21 

9 
9 
9 
9 
9 

19 
18 
9 
9 
12 
12 

5 
9 
9 
9 
9 

21 

21 

50 

Table  4 — Percentage  of  Coal  Extracted  from  Bed 


91 
55 

92 
68 

93 
75 

94 
81 

95 

82 

97 

Per  cent  of  extraction 

68 

Such  a  high  percentage  of  extraction  leaves  large   areas  of  roof 
unsupported  by  pillars  and  causes  frequent  squeezes.     Few  mines  in  the 


Fig.  7.    Tongue-and-goove  lining  of  overcast 


district  have  been  free  from  squeezes  and  in  some  instances  the  operating 
companies  have  become  involved  in  litigation  over  damage  to  surface 
improvements  through  surface  subsidence.     Fig.  6  shows  a  surface  sub- 


MINING   PRACTICE 


19 


sidence  caused  in  1904  by  a  squeeze  in  the  mine  underlying  at  a  depth 
of  210  feet.  The  loss  of  coal  by  squeezes  and  the  cost  of  re-driving 
entries  through  squeeze  areas  add  to  the  cost  of  mining  coal,  yet  in 
several  mines  narrow  pillars  and  wide  rooms  were  found,  although  the 
same  dimensions  had  caused  squeezes  in  the  past. 

More  serious  than  the  additional  cost  of  mining  is  the  loss  of  life 
due  to  unsafe  working  dimensions.  The  record  of  this  district  with 
respect  to  fatal  and  non-fatal  injuries  is  bad.  The  miners  of  the  dis- 
trict are  largely  of  foreign  birth;  Italians.  Lithuanians,  and  Poles  pre- 


side Elevation 


Plan 

Fig.  8.    Customary  method  of  placing  shots  in  undercut  face 


dominating,  and  it  requires  constant  vigilance  on  the  part  of  the  operators 
to  secure  observance  of  the  simplest  rules  for  sale  mining.  The  causes 
contributing  to  the  excessive  accident  rate  of  the  district  are: 

Treacherous  roof. 

Unsafe  dimensions  of  working. 

Lax  discipline  at  the  face. 

More  face-bosses  with  defined  power  to  enforce  safe  propping  of  the 
roof  at  the  working  face  would  undoubtedly  decrease  the  number  of 
accidents. 

Table  5  gives  the  comparative  records  for  accidents  of  the  State 
and  the  district  for  the  years  1909,  1910,  1911,  and  1912.  It  will  be 
seen  that  in  spite  of  the  efforts  of  the  operators  to  decrease  the  risk  of 
mining  by  widening  entries  and  by  calling  the  attention  of  the  men  to 
the  dangers  of  their  occupation,  no  marked  improvement  lias  been 
brought  about  in  the  district  as  a  whole.  The  miner  will  not  take  proper 
measures  for  his  own  protection  unless  \w  is  compelled  to  do  so  and 
until  defined  power  is  given  to  face  bosses  the  yearly  death  roll  will 
retain  approximately  its  present  size.  Table  6  gives  an  analysis  of  the 
causes  of  fatal  and  non-fatal  accidents  in  District  YITI  and  in  all  the 
other  districts  of  the  State  combined  for  the  vear  ending  June  30.  1!M*2: 


20 


COAL    MINING    INVESTIGATIONS 


Table    5 — Relation   Between   Accidents,   Number    of   Employees,   and 

Tonnage 


State 

District  VIII 

1909    !    1910 

1911 

1912 

1909 

1910 

1911 

1912 

Number  men  killed 

213 

894 

230, 816 

54, 993 
'  2.9 
10.7 

406 
742 

120,  000 

65,  657 
5.4 
9.9 

157 

709 

319, 523 

70,  754 
2.0 
9.2 

180 
800 

319,  524 

71,  893 
2.3 
10.1 

12 
56 

185, 136 

39, 672 
3.7 
17.5 

11 
35 

184, 860 

58,099 
3.3 
9.6 

21 
39 

142, 207 

81,  769 
5.7 
10.0 

18 

Number  men  seriously  injured. . . . 

Number  tons  mined  to  each  man 

killed 

59 

187,  469 

Number  tons  mined  to  each  man 
seriously  injured 

57, 194 

Number  killed  per  1,000  employees 
Number  injured  per  1,00  employees 

4.5 
14.7 

It  will  be  seen  from  this  table  that  although  the  per  cent  of  non- 
fatal accidents  from  fall  of  rock  or  coal  is  only  slightly  in  excess  of  the 
rate  for  all  the  other  districts  combined,  the  per  cent  of  fatal  injuries 
from  this  cause  is  excessively  high.  The  desire  of  the  present  operating 
companies  to  prevent  accidents  is  shown  in  several  mines  in  the  district 
where  entries  have  been  widened  and  retimbered  to  provide  safe  passage- 
ways, dangerous  curves  have  been  eased,  and  the  roadbed  thoroughly 
cleaned. 


Table    6 — Causes   of  Accidents   in   District    VIII  and  in    All   Other 
Districts  Combined,  1912* 


Cause 


FATAL  ACCIDENTS 

Per  cent  from  falling  coal  or  rock 

Per  cent  from  pit-cars 

Per  cent  from  explosives 

NON-FATAL  ACCIDENTS 

Per  cent  from  falling  coal  or  rock 

Per  cent  from  pit-cars 

Per  cent  from  explosives 


District 
VIII 


77.7 
5.5 
5.5 


47.5 

27.1 

5.1 


*  Thirty-first  Annual  Coal  Report  of  Illinois. 

The  operators  of  the  larger  mines  have  taken  precautionary  measures 
against  fire,  and  the  fire  protection  at  mine  No.  93  is  especially  good. 
At  this  mine  the  method  of  conveying  lubricating  oil  to  the  shaft- 
bottom  is  unusual  in  the  district,  and,  indeed,  in  the  State.  On  the 
surface  at  a  distance  of  100  feet  from  the  hoisting  shaft  three  oil  tanks 
are  sunk  5  feet  deep  in  the  ground.  One  tank  of  400  gallons  capacity 
contains  black  oil;  one  of  250  gallons  capacity  contains  engine  oil;  and 
a  third  of  200  gallons  capacity  holds  cylinder  oil.  Pipes  from  these 
tanks  are  carried  down  the  pipe-way  in  the  hoisting-shaft  and  the  various 
oils  are  pumped  direct  to  the  bottom  as  needed.  This  method  obviates 
the  necessity  of  taking  oil  into  the  shaft  in  barrels  or  in  cans  and  does 
awav  with  storing  oil  in  the  run-around. 


21 


"mrw~m^^r~7^r-?^    &   m 


Fig.  9.    Sketch  of  three-piece  gangway  sets 


22 


COAL   MIXING    INVESTIGATIONS 


In  the  majority  of  mines  in  the  district  the  mules  are  stabled  under- 
ground. In  some  cases  the  hoisting-shaft  is  too  small  to  permit  daily 
hoisting  of  mules,  but  the  fire-risk  from  underground  stabling  in  the 
district  is  minimized  as  much  as  possible  in  the  larger  mines.  The  trans- 
portation of  hay  from  the  surface  to  the  stables  and  its  exposure  in  the 
mangers  at  feeding  time  is  always  a  source  of  danger.  Although  the 
provisions  of  the  State  law  in  regard  to  transportation  of  hay  and  its 
storage  underground,  if  followed,  give  reasonable  security  against  fire 
from  this  source,  many  operators  in  the  State  prefer  to  stable  their 
mules  on  the  surface.  In  mine  No.  52,  located  in  Southern  Illinois,  it 
costs  $0.000037  per  ton  of  coal  hoisted  to  lower  each  mule  daily.  The 
company  has  twenty-four  mules  underground  and  the  total  time  con- 
sumed in  lowering  them  is  thirty  minutes.  The  same  time  is  required 
to  hoist  them.  The  total  cost  of  lowering  and  hoisting  twenty-four 
mules  daily  is  $0.000888  per  ton  of  coal  hoisted.  Fire-risk  is  thus 
avoided  and  the  animals  are  kept  in  better  condition. 


Table  7 — Per  Capita  Production  of  Employees 


Mine  number 

District 
in  fiscal 
year  1912 

All  other 
districts 
combined 

91 

92 

93 

94 

95 

97 

in  fiscal 
year  1912* 

1,250 

265 

25 

240 

159 

9.6 

4.7 

50 

5.2 

7.8 

150 

40 

5 

35 

16 

7.0 

3.8 
30 
4.3 
9.4 

2,600 
620 
20 
600 

411 

30.0 

4.2 

130 

4.3 

6.3 

soo 

230 

20 
210 

180 

10.5 

3.5 

40 

3.9 

4.4 

50 
9 
2 

7 

7 
3.5 
5.6 
25 
7.1 
7.1 

300 
78 
8 
70 

48 

8.7 

3.8 

37.5 

4.3 

5.4 

18, 339 

4,007 

305 

3,702 

*2,  506 

12.2 

4.6 
60.1 

4.9 
*6.0 

311, 021 
72, 634 
6,226 
66,  408 

50, 812 

10.7 

Number  underground  employees 

Number  miners,  loaders  and  mach- 

Number  underground  employees  per 

Tons  of  coal  per  day  per  each  em- 

4.3 

Tons  of  coal  per  day  per  each  surface 

49.9 

Tons  of  coal  per  day  per  each  under- 

4.7 

Tons  of  coal  per  day  per  face  worker 
(miners, loaders  and  machine  men) 

6.1 

*  Shipping  mines  only. 

The  production  of  employees  at  each  mine  examined  is  shown  in 
Table  7.  The  number  of  underground  employees  per  each  surface  em- 
ployee in  the  district  is  high  compared  with  the  number  for  the  shipping 
mines  of  the  other  districts  combined  because  several  mines  in  District 
VIII  have  surface  and  general  roustabout  work  well  systematized. 


VENTILATION 

In  the  mines  of  large  tonnage  in  this  district  the  ventilation  of  the 
workings  is  excellent  and  the  air  supply  is  in  excess  of  legal  require- 
ments. The  air  at  the  working  face  is  as  pure  as  mine  air  reasonably 
can  be  expected  to  be.  Table  8  gives  data  on  ventilating  equipment  for 
each  mine  examined. 


MINING    PRACTICE  23 

Table  8 — Data  on  Ventilating  Equipment 


No. 

of 

mine 


Air-shaft 


Depth 
in  feet 


Size  Number 
in  clear  compart- 
in  feet        ments 


Lining 


Fan 


Type 


Diameter 
in  feet 


Width 
of  blade 
in  feet 


Material 

of 
fan-house 


217 
240 

186 

8    by  12 
6    by  14 
8    by  12 

2 
2 
2 

90 

40 

223 

7    by  14 
4§  by    H 
6"  by  10" 

2 

1 
2 

Timber 

..do 

One  timber,  one  con 

crete 

Timber 

..do 

..do 


Capell. 
..do.. 


..do... 
..do... 
Paddle. 
Capell.. 


Timber 
..do... 

..do... 
..do... 
..do... 
..do... 


Explosive  gas  is  seldom  found  in  active  workings,  and  even  in 
abandoned  workings  is  found  only  in  small  quantity.  In  the  history  of 
the  district  there  have  occurred  a  few  minor  gas  explosions. 

The  coal  of  this  district  when  air-dried  and  tested  in  the  laboratory 
at  Urbana  is  the  most  explosible  of  all  the  coals  in  the  State,  and  in 
the  rooms,  the  rib-dust  when  dry,  and  the  dust  in  suspension  in  the  air, 
are  more  explosible  than  the  dust  in  rooms  in  other  districts.  The 
average  pressure  developed  by  the  coal  dust  when  tested  in  the  explosi- 
bility  apparatus  at  the  laboratory  at  Urbana  is  compared  with  the 
pressures  developed  by  the  coal-dust  of  other  districts  in  Table  9. 


Table  9 — Pressures  Developed  by  Face  Samples  in  Explosioility 

Apparatus 


District 

Number 

samples 

Pressure  m 
pounds 

per  square 
inch  at 
2,192  °F 

j 

17 

16 

24 

6 

3 

II 

."     VN(> 

Ill 

IV 

7  700' 

V 

7  105 

VI 

"i  950 

vii....: 

7   17.">. 

VIII  Danville 

v  925 

IX 

Although  the  ribrdusl  of  the  rooms  is  very  explosive  when  dry,  it  is 
not  very  explosible  as  found  on  the  ribs  because  it  has  such  a  high 
moisture  content.  The  moisture  contained  in  rib-dust  samples  of 
District  VIII  as  received  at  the  laboratory  in  Urbana  averages  25.31 

per  cent  as  compared  with  12.2-1  per  eeni  for  all  the  oilier  districts  of 
the  State.  The  rib-dust  and  road-dust  of  the  haulage-ways  contain  a 
large  amount  of  inert  -hale  supplied  through  the  -rinding  of  the 
numerous  roof-falls  by  car  wheels  and  by  the  feet  of  men  and  mules. 
The  ash  in  haulage-way  rib-dusts  averages  38.59  per  cent  for  the  Dan- 
ville district.  All  rib-dusts  in  the  district  are  constantly  damp  even  in 
winter  and  the  uniform  seepage  of  surface  water,  due  to  the  shallowness 
of  the  workings  renews  the  mechanicallv-held  moisture  as  fast   as  it  is 


24 


COAL    MINING    INVESTIGATIONS 


evaporated  by  the  ventilating  current.  Consequently  the  relative  hum- 
idity of  the  mine  air  is  high,  both  in  the  return  air  current  and  in  the 
rooms.  Table  10  gives  readings  taken  with  a  sling  psychrometer  on  the 
surface  and  in  the  return  air-current  and  at  the  working  face. 


Table  10 — Humidity  Data  for  District  VIII 


No. 

Date 

Surface  readings 

Readings  in  rooms 

Readings  in  return 
air-course 

of 
mine 

Tem- 
pera- 
ture °F 

Relative 
humidity 
per  cent 

Tem- 
pera- 
ture °F 

Relative 
humidity 
per  cent 

Tem- 
pera- 
ture^ 

Relative 
humidity 
per  cent 

Remarks 

91 

Mar. 
Feb. 
Feb. 
Mar. 
Mar. 

Mar. 

11,  1912 

28,  1912 

27,  1912 

7,  1912 

4,  1912 

14,  1912 

35.0 
26.2 
20.2 
26.2 
27.  2 

42.0 

100 
64 
85 
97 
73 

84 

64.5 
56.0 
62.5 
63.0 
56.0 

63.2 

92 
94 

95* 

84.5 

88.5 

50.5 
43.5 
58.7 
63.0 

93 
90 
98.5 
95 

92 

93 

94 

95 

This  mine  has  main  en- 

97 

53.0 

91 

try  length  of  only  600 
feet 

The  necessity  for  humidifying  mine-air  to  prevent  coal-dust 
explosions  is  obviated  by  the  high  natural  humidity  of  the  mines  due 
to  the  uniform  seepage  throughout  the  workings  and  by  the  high  ash 
content  of  the  rib-dusts.    In  only  one  of  the  mines  examined  was  steam 


Fig.  10.     Timbering  in  haulage  entry 


exhausted  into  the  air-shaft  and  in  this  case  it  was  done  to  prevent  the 
formation  of  ice  in  the  shaft  in  winter.    In  two  of  the  mines  examined, 
sections  of  the  mine  in  which  the  floor  had  become  dry  were  sprinkled 
with  water  by  cars  occasionally  for  the  purpose  of  laying  the  dust. 
Table  11  gives  the"  method  and  frequency  of  humidification. 


MINING    PRACTICE 

Table  11 — Method  and  Frequency  of  Humidification 


Mine 
No. 

Method  of  humidifying 

Frequency  of  humidifying 

91 

92 

No  humidification 

93 

Sprinkling  by  cars 

94 

No  humidification 

95 

No  humidification 

97 

Sprinkling  by  cars 

Once  each  month 

In  the  larger  mines  the  use  of  concrete  monolith  stoppings  is  com- 
mon and  the  usual  proportions  of  concrete  are:  1  Portland  cement; 
5  unsifted  cinders.  Large  cinders  and  clinkers  are  picked  out  by  hand. 
This  concrete  is  suitable  for  mine  use  but  it  is  probable  that  stoppings 
could  be  built  more  cheaply  if  concrete  blocks  were  made  on  the  surface 
and  distributed  as  needed  throughout  the  mine.  Table  12  gives  costs  of 
various  types  of  efficient  stoppings  as  constructed  in  Illinois.  The 
efficiency  of  stoppings  depends  equally  upon  the  material  of  which  they 
are  constructed  and  the  tightness  of  the  joint  between  the  stopping  and 
ribs,  floor  and  roof.  In  some  mines  in  the  district  where  sufficiently  deep 
cuts  in  ribs  and  floor  were  not  made,  leaks  have  developed  due  to  rashing 
off  of  the  rib  coal  and  disintegration  of  the  fire-clay  floor. 


Table  12 — Cost  and  Material  of  Efficient  Stoppings 


District 


Material 
of  stopping 


Proportions 

of  concrete         g  .- 


-  - 


Cost  in  cents 
per  square 
foot  in  place 


V  or  Southern. 


Concrete  blocks. 


VI 

VI 

VI 

VII 

VIII  or  Danville.. 


Concrete  monolitl 


Concrete  monolith 


Brick  coated  with 
cement 


Concrete  blocks.. 


Concrete  monolith 


i  cement;  2  sharp 
washed  sand;   1 
crushed  lime 
stone 


l  cemenl ;  »i  sifted 

I'imi.Ts 


l  cemenl ;  -'  sand 
5  slack  from 
floor 


l  cement;  0  crush- 
ed cinders. . 


i  cemenl ;  .">  unsif- 
ted cindei 


L2 


L0.6 


I.:,    6 


9.  )    7.  2 


Size  of 

blocks 

in  inches 


Remarks 


s    I.  I    ti.  2 


8   11.(1   II. 

I 


21.6 


11.  I 


15. 0 

in.  i; 


10.6 


25.  1 


8  x  12  x  24 


8 x8 x  Ki 


i  rnnecessary 
aggregate. 

Blocks    weigh 
ISO  pounds. 
Labor    costs    8 
cents  per  block 

To  replace  ex- 
panded metal 
and  wood-fibre. 


Brick     COSl     $9.00 

per  Jkf.  delivered 

One  man  builds 

one  stopping,  7 

f»H>t    by    12    feel, 
in  2  days 

Blocks  cost  6 
cents  each   at 
pitmouth 


26 


COAL    MINING   INVESTIGATIONS 


The  overcasts  in  the  larger  mines  are  often  built  of  brick  or  con- 
crete and  in  some  instances  are  lined  with  i/o-inch  tongue-and-groove  as 
shown  in  Fig.  7.  Lining  the  overcast  prevents  the  filling  of  the  air- 
conrse  in  the  overcast  with  an  accumulation  of  small  roof-falls  which 
choke  the  ventilating  current. 

BLASTING 

In  only  four  of  the  forty-nine  mines  of  the  district  is  coal  undercut 
by  machines,  but  the  tonnage  of  undercut  coal  totaled  683,789  tons 
during  the  year  ending  June  30,  1912,  which  amount  is  20.2  per  cent  of 
the  output  of  the  district.  Electric  chain  machines  are  used  exclusively, 
and  the  average  cut  is  6  feet  deep.  The  customary  method  of  placing 
shots  in  an  undercut  face  is  shown  in  Fig.  8. 


Fig.  11.     Destruction  of  timber  by  crushing 


The  tonnage  produced  by  shooting  off  the  solid  was  79.8  per  cent  of 
the  total  tonnage  of  the  district  for  the  fiscal  year  1912  and,  as  in  other 
districts,  this  method  of  shooting  is  responsible  for  great  economic  waste 
through  increasing  the  amount  of  slack  coal.  The  use  of  powder  is 
excessive  and  overcharged  shots  weaken  the  roof  and  contribute  largely 
to  the  accidents  from  roof-fall.  During  the  year  ending  June  30,  1912, 
the  average  yield  in  the  district  was  28.6  tons  of  coal  per  25-pound  keg 
of  powder.  In  the  mines  shooting  off  the  solid  the  shooting  is  done  off 
the  weak  rib;  a  round  usually  comprising  four  holes:  two  rib  shots  and 
two  center  shots.  The  depth  of  holes  as  measured  in  several  mines  was 
6  to  7  feet  and  the  most  common  diameter  was  2*4  inches.  The  custom 
of  the  miners  is  to  put  2y2  feet  of  dummies  in  a  7-foot  hole,  leaving  in 
a  hole  4%  feet  of  powder  in  a  bed  averaging  51/,  feet  in  thickness. 

Black  powder  was  used  exclusively  at  each  of  the  mines  examined 
and  was  contained  in  steel  kegs:  the  mines  being  considered  too  wet  to 


MINING   PRACTICE 


27 


allow  the  use  of  paper  kegs.     In  this  district  and  also  in  every  district 
in  the   State  where  the  steel  powder  keg  is  used  almost  every  empty 


Fig.  12.    Roof-fall  in  room 


powder  keg  examined  had  in  the  head  a  square  hole  made  by  a  pick. 
Familiarity  with  the  use  of  powder  breeds  careless  handling  and  it  is 
difficult  to  prevent  the  opening  of  powder  kegs  with  a  pick.     Even  if 


Fig.  13.     Roof-fall  in  entry 


the  pick-hole  in  the  head  is  imi  made  until  after  part  of:  the  powder  lias 
li'vii  removed  from  the  keg  the  danger  of  igniting  the  remaining  powder 


28 


COAL    MINING    INVESTIGATIONS 


is  great.  The  provision  of  the  State  mining  law  making  it  a  criminal 
offense  for  any  person  to  have  in  his  possession  in  any  mine  a  powder 
keg  with  a  pick-hole  in  it  should  be  enforced. 

There  exists  a  common  disregard  of  the  State  law  prohibiting  the 
use  of  "bug-dust"  for  tamping  material  and  unless  shot-firers  refuse  to 
fire  shots  tamped  with  coal-cuttings  the  miner  ordinarily  uses  them  for 
tamping  because  it  requires  extra  labor  to  obtain  fire-clay. 

In  some  mines  in  the  district  the  powder  kegs  are  placed  in  a 
specially  constructed  covered  car  for  transportation  to  the  working  places 
and  are  taken  into  the  mine  after  the  men  have  left  the  mine  and  when 
no  current  is  on  the  trolley  wires.  In  many  of  the  mines,  however,  the 
kegs  are  carried  into  the  mine  on  ordinary  open  pit  cars.  Recent 
explosions  of  powder  in  the  State  during  delivery  to  the  miners  have 
demonstrated  that  more  care  should  be  exercised  to  prevent  accidents 
during  transportation  to  the  working  places. 

No  fire-runners  were  employed  at  any  of  the  mines  visited  because 
fires  after  shots  are  of  very  rare  occurrence  in  the  district. 

Table  13  gives  data  on  blasting  practice  for  each  mine  examined. 
The  figures  for  tons  of  coal  gained  per  keg  of  powder  and  per  cent  of 
lump  coal  were  obtained  from  the  books  of  the  various  companies  and 
are  averages  for  1910  and  1911. 

Table  13 — Blasting  Practice 


Undercut  or  shot  off 
the  solid 


Oh 

Fuse. 

..do. 
..do. 

..do. 

Squib 
Fuse. 


I  -- 

U     L 

M_ 

ate 

13 

ao 

ap 
§1 

t3  o 

If 

a> 

a 

o. 

O  «-, 

8  ° 

««      O 

0+3 

tC 

®  5 

ft 

o  © 

fl^ 

o 

2£ 

cfl  W> 

Z%2 

AS 

3  a 

*s 

6 

.a 

O    W 

CO 

Ph 

H 

Ph 

£ 

fc 

Remarks 


91 


Shot  off  the  solid. 


Shot  off  the  solid. 
Undercut 


94  Shot  off  the  solid. . . 

95  Shot  off  the  solid. . . 
97 1  Shot  off  the  solid. .. 


2^ 

7 

2! 

7 

2i 

6 

2* 

6 

2k 

6 

n 

8 

C 

1.00 

25 

$0.07 

40 

2 

125 

c 

1.00 

25 

.07 

70 

2 

35 

F 

0.21 

120 

.015 

65 

4 

200 

c 

0.96 

26 

.067 

60 

2 

150 

c 

0.57 

44 

.04 

55 

0 

0 

c 

1.25 

20 

.088 

50 

2 

60 

Average  daily  output 
for  each  miner  is  seven 
tons 

Machine  makes  six  foot 
cut 


TIMBERING 

The  treacherous  roof  of  the  Danville  district  necessitates  careful 
timbering  in  entries  and  close  propping  in  rooms  with  the  result  that 
the  timbering  charge  per  ton  of  coal  mined  is  unusually  heavy.  The 
roof  along  the  permanent  haulage-ways  falls  badly  unless  supported,  and 
it  is  often  necessary  to  lag  the  sets  for  several  hundred  feet  along  the 
entry  when  going  through  areas  of  bad  roof.  In  the  shipping  mines 
timbering  of  the  permanent  entries  is  well  done  and  a  great  eitort  is 
made  by  the  operators  to  render  the  haulage  entries  safe.  At  each  mine 
examined  the  three-piece  gangway-set  was  used,  either  with  two  long  legs, 
with  one  leg  short  and  the  other  long,  or  with  two  short  legs  resting  in 
latches  cut  in  the  ribs.     Where  a  curve  occurs  in  the  entrv  the  short- 


MINIMI    PRACTICE 


29 


legged  frames  are  commonly  used  because  with  long-legged  frames  there 
exists  the  danger  of  breaking  the  legs  and  bringing  down  bad  falls  if  a 
trip  jumps  the  track.  Fig.  9  shows  the  methods  of  leg  arrangement  in 
the  three-piece  gangway  set. 

Fig.  10  shows  typical  timbering  of  a  haulage  entry,  the  legs  and 
cross-bars  being  of  6-inch  oak. 

The  high  relative  humidity  of  air  in  the  return  and  the  constant 
temperature  of  about  65  degrees  are  very  favorable  to  sporegrowth  and 
consequently  mine  timbers  decay  rapidly  and  fail.  The  average  life 
of  timber  at  the  mines  examined  was  eighteen  months.  The  gangway-set 
when  weakened  bv  decav  usuallv  fails  in  the  cross-bar  which  is  more 


FlG.  14.     Method  of  propping  ncai  face  of  room 


difficult  to  replace  than  are  the  legs.  With  a  view  of  avoiding  roof  falls 
from  breaking  cross-bars  and  of  lessening  the  timbering  expense  which 
is  constantly  increasing  on  account  of  the  increasing  cost  and  the  poor 
quality  of  available  timber,  several  mines  are  substituting  steel  I-beams 
for  timber  cross-bars,  but  retaining  timber  legs  in  the  permanent  entries. 
The  standard  I-beam  of  structural  steel  which  combines  a  high  degree 
of  resistance  to  bending  with  minimum  weight  of  metal  has  proved  well 
fitted  for  use  in  mines.  In  the  Danville  district  there  are  the  following 
relations  between  sizes  of  steel  I-beams  and  length  of  span: 

Span  in  feet  Size  of  I-beam  in  inches 

I 
6 


8 
10 
12 
16 


12 


With  this  system  frames  are  spaced  on  2i/2-f°ot  centers.  Eight- 
inch  diameter  rough  white  oak  legs  are  used  with  spans  of  8  and  12  feet, 
and  10-inch  legs  are  used  for  greater  spans. 


30 


COAL    MIXING   INVESTIGATIONS 


Old  railroad  rails  have  been  used  as  cross-bars  in  a  few  mines.  In 
one  mine  rising  60-pound  rails  as  cross-bars  the  rails  failed  under  the 
roof  weight  on  account  of  the  crystalization  of  the  rail.  Eails  break 
easily  under  bending  stress  because  of  the  high  carbon  content  of  the 
steel  from  which  they  are  made. 

It  is  an  open  question  whether  or  not  the  use  of  white  oak  legs  with 
steel  I-beam  cross-bars  is  an  economy  in  permanent  timbering.     The 


• 

1— 
M        1- 

• 

■•■' 

^ 

"1 
3 

-0  v/WJ.'..       ||B   H 

Fig.  15.    Plan  of  room,  showing  propping 


first  cost  of  a  4-inch  28-pound  steel  leg  6  feet  in  length  would  be 
approximately  $4.00,  delivered  in  the  mine.  An  8-inch  round  white  oak 
leg  6  feet  long  costs,  delivered  in  the  mine,  approximately  50  cents. 
To  the  cost  of  replacement  of  white  oak  legs  during  the  life  of  the  mine 
must  be  added  the  cost  of  fire  hazard  and  increased  insurance  rate. 

None  of  the  mines  examined  attempted  to  give  preservative  treat- 
ment   to    mine    timber,    because    under    the    unusual    roof    conditions 


MINING    PRACTICE 


ol 


obtaining  in  the  district  it  is  not  regarded  as  economy  to  apply  preserva- 
tive   treatment   which   equals   at   least   the   first   cost   of   the   timber   to 


[i 


Fig.  16.    Steel  I-beams  and  brick  pillars  at  bottom 


material  liable  to  destruction  by  crushing,  as  shown  in  Fig.  11,  within 
a  few  months  after  its  installation. 


Fig.  17.    Inby  end  of  concrete-lined  bottom 


The  greatest  menace  to  the  life  of  the  miner  in  this  districi  is  the 
treacherous  roof,  and  consequently  adequate  propping  in  rooms  is  com- 
pelled  by  the  larger  operating  companies;  but   in  the   mines  of  small 


32  COAL    MINING    INVESTIGATIONS 

capacity  discipline  is  more  lax,  and  the  miner  is  not  compelled  to  keep 
his  props  close  to  the  face.  There  is  danger  in  failure  to  keep  the  props 
within  12  or  15  feet  from  the  working  face  in  a  district  where  it  is 
often  necessary  to  have  cross-bars  across  the  track  and  along  the  ribs, 
yet  it  is  only  by  constant  diligence  on  the  part  of  officials  that  the  miners 
can  be  made  to  keep  their  places  safe.  The  necessity  for  close  propping 
is  greater  in  this  district  than  in  many  others  in  the  State  because  the 
numerous  "nigger-heads"  or  "sulphur-balls"  which  protrude  from  the 
roof  have  little  cohesion  to  the  roof  shale.  The  accident  record  of  the 
district  shows  the  need  of  greater  vigilance  on  the  part  of  mine  officials 
and  greater  regard  for  their  own  safety  on  the  part  of  the  miners.  The 
district  during  the  year  ending  June  30,  1912,  produced  5.8  per  cent 
of  the  coal  mined  in  Illinois  and  the  number  of  days  work  performed 
was  5.8  per  cent  of  the  days  work  performed  in  coal  mines  in  the  State. 


Fig.  18.    Concrete  and  steel-I-beam  in  slope  bottom 

It  should  therefore  have  furnished  5.8  per  cent  of  the  accidents  occurring 
in  the  State,  but  with  fifty-nine  non-fatal  accidents  it  supplied  7.4  per 
cent  of  the  non-fatal  accidents  and  with  eighteen  fatal  accidents  it 
supplied  10  per  cent  of  the  fatal  accidents.  Of  the  non-fatal  accidents 
in  the  district  47.5  per  cent  were  caused  by  falls  of  rock  and  coal  as 
compared  with  45.5  per  cent  from  this  cause  for  the  State  as  a  whole. 
Of  the  fatal  accidents  77.7  per  cent  were  caused  by  falls  of  rock  and 
coal  as  against  54.4  for  the  State.  Figs.  12  and  13  show  typical  roof 
falls  in  the  district. 

At  each  mine  examined  the  props  were  counted  in  place  in  a 
measured  length  in  each  of  several  typical  rooms.  The  width  of  these 
rooms  was  measured  and  there  was  thus  obtained  the  average  number 
of  props  per  hundred  square  feet  of  roof.  For  each  mine  visited  the 
number  of  props  per  100  square  feet  of  roof  and  other  data  concerning 
propping  are  given  in  Table  14.     The  figures  referring  to  the  number 


MINING   PEACTICE 


33 


and  cost  of  props  per  ton  of  coal  were  obtained  in  each  case  from  the 
books  of  the  operating  company.  Fig.  1-1  shows  the  face  of  a  typical 
room  in  one  of  the  larger  mines.  Here,  props  are  placed  within  12  feet 
of  the  face,  allowing  only  sufficient  space  between  the  last  prop  and  the 
face  for  the  operation  of  an  undercutting  machine.  Fig.  15  shows  a 
plan  of  a  typical  room  in  a  mine  where  adequate  propping  is  insisted 
upon. 

The  roof  of  the  "shaft  bottom"  in  nearly  all  the  larger  mines  in 
the  district  is  supported  by  concrete  or  steel.  Fig.  16  shows  the  arrange- 
ment of  a  bottom  wliere  brick  pillars  13  inches  by  18  inches  set  on  8-foot 
centers  support  4-inch  steel  I-beams  on  which  are  laid  2-inch  by  6-inch 
planks  for  lagging.  The  pillars  are  7  feet  high.  This  arrangement 
gives  a  bottom  free  from  the  danger  of  roof-falls  but  not  fire-proof. 

Fig.  17  shows  the  inby  end  of  a  concrete  bottom.  The  walls  of  the 
lining  of  the  entry  are  24  inches  thick  at  the  bottom  and  the  thickness 
of  concrete  is  gradually  reduced  till  at  the  top  of  the  arch  it  is  12  inches. 
A  gob  filling  is  packed  between  the  arch  and  the  roof.  The  length  of 
concrete  bottom  on  each  side  of  the  shaft  is  165  feet.  The  concrete  was 
made  in  the  following  proportions;  1  Portland  cement*  1  sand:  4  washed 


Table  14 — Data  Concerning  Props  in  Rooms 


Number 
per  100 
square 

feet 
of  roof 

Cost  in 

cents  per 

100  square 

feet 

of  roof 

Diam- 
eter in 
inches 

Length 
in  feet 

Life  in 
months 

Distance 
in   feet  of 

nearest 

prop 

from    face 

Per  ton  of  coal 

No.  of  mine 

Number 

Cost  in 

cents 

91 

3.1 

5.  1 

•■',.  L 
7.  6 
.").  0 

6.  3 

20.9 
44.  ti 
24.  S 
41.8 
37.  r> 
44.1 

5                   fi 

is 

is 

18 

is 
is 
21 

If, 
17) 
IS 
11 

0.  27) 
0.31 

II.  is 

1.7 

92 

1.7 

93 

1.  2 

94 

4 
6 
4 

1 

95 

2.-» 
14 

97 

0.33 

2.3 

Fig.  18  shows  a  slope  bottom  where  concrete  is  placed  mi  the  top 
of  coal  which  is  5  feet  9  inches  thick  ;il  tin-  point.  The  wall  is  2  feet 
high  and  9  inches  thick  and  the  concrete  has  the  proportions:  1  Portland 
cement;  6  river-washed  gravel.  Ten-inch  steel  [-beams,  weighing  40 
pounds  to  the  lineal  fool,  are  placed  on  2 '  .j-l'ooi  centers  across  the 
caging-room  to  supporl  (lie  roof,  ami  the  space  between  the  [-beams  is 
filled  with  concreie,  thus  providing  a  water-proofed  roof,  li  is  doubtful 
if  placing  concrete  on  l<»|i  of  the  coal  will  he  successful,  for  if  the  coal 
spalls  off  rapidly  this  arrangement    will   nol   he  permanent. 

In  the  lining  of  shafts  and  slopes  in  the  district  timber  is  princi- 
pally used.  Nearly  all  the  shafts  were  sunk  before  the  State  law  requiring 
fire-proofed  shafts  was  passed. 

Fig.  3  shows  a  concrete-lined  slope  which  is  his  Peel  long  from 
the  surface  to  the  hottom.  ]  feel  wide,  and  8  feel  high.  The  concrete 
sides  are  6  foot  high  ami  9  inches  thick.  Placed  mi  2y2-iooi  centers 
along  the  concrete  wall  are  white  oak  legs  6  inches  in  diameter  and  18 
inches  long  which   support    56-pound    rails   on    which   the   lagging   rests. 


34 


COAL    MIXING    INVESTIGATIONS 


HAULAGE 

Few  mines  in  the  district  have  a  daily  production  of  over  1,500 
tons,  and  mules  are  generally  used  on  both  main  and  secondary  haulage. 
Six  mines  are  provided  with  electric  locomotives  on  the  main  haulage 
and  in  one  mine  haulage  is  done  by  cable  on  the  main  entries.  The  bad 
condition  of  the  secondary  haulage  roads  makes  the  use  of  gathering 
locomotives  unprofitable  and  although  they  have  been  tried  in  this  dis- 
trict their  use  has  been  discontinued  and  mules  are  universally  used  for 
gathering.  A  decrease  in  the  cost  of  mining  in  this  district  can  probably 
be  made  by  bettering  the  condition  of  the  haulage-ways.  More  attention 
advantageously  could  be  paid  to  maintaining  easy  grades  and  curves. 
As  beds  6  and  7  lie  practically  flat,  easy  grades  can  be  maintained  with 


Fig.  19.    Typical  caging-place  at  shaft-bottom 


very  little  brushing  of  roof  and  floor.  The  tendency  of  the  floor  to 
heave  is  mainly  caused  by  excess  weight  on  pillars  of  insufficient  size. 
The  present  operators  of  the  mines  of  large  output  did  not  project  the 
mines  and  are,  therefore,  not  responsible  for  the  poor  condition  of  the 
haulage-ways,  and  a  successful  effort  is  being  made  in  some  mines  to 
improve  the  uneconomical  haulage. 

Rails  in  the  main  haulage  often  weigh  only  16  pounds  and  16-pound 
rails  are  used  on  the  secondary  haulage  at  all  mines.  The  track-gage 
varies  from  36  to  38  inches.  At  each  mine  examined  wooden  rails  are 
used  in  the  rooms.  In  the  shipping  mines  ties  are  usually  5  inches  by 
6  inches  by  5  feet  and  are  generally  of  white  oak.  Pit  cars  often  are 
not  kept  in  good  repair,  and  the  constant  dropping  of  coal  from  these 


35 


Jb  COAL    MIXING    INVESTIGATIONS 

cars  to  the   track   and   the  presence   of   gob   along  the   track   in   maxiy 
instances  hinder  rapid  and  cheap  haulage. 

The  shaft  bottoms  in  the  district  are  too  short  for  the  most 
economical  handling  of  the  output  but  the  short  bottom  is  a  product  of 
an  earlier  period  and  is  found  throughout  the  State.  Table  15  gives 
haulage  data  for  the  six  shipping  mines  examined. 


Fig.  21.    Island  of  overburden  of  stripping  mine 

With  the  widening  of  haulage  entries  in  dangerous  places  since  the 
present  operating  companies  took  over  the  large  mines,  the  percentage 
of  fatal  accidents  clue  to  pit  cars  has  decreased  till  in  1912  the  per  cent 
of  fatal  accidents  from  this  cause  was  5.5  for  the  district,  as  against 
18.8  for  the  State,  and  the  per  cent  of  non-fatal  accidents  27.1  for  the 
district,  as  compared  to  26.3  for  the  State. 


Table  15 — Haulage  Items 


No. 

of 

mine 

Kind  of  haulage  on  main-entries 

Weight  of 
mine  cars 
in  pounds 

Capacity 
of  cars 
in  tons 

Main-entry 

rail 

weight  in 

pounds  per 

yard 

Track  gage 

91 

1,800 
1,150 
2,200 
1,800 
1,200 
1,200 

24 
11 

2i 
11 
1 
1 

30 
16 
30 
16 
16 
16 

38 

92 

Mule 

38 

93 

38 

94 

Main  and  tail-rope 

36 

95 
97 

Mule 

Mule 

38 
36 

HOISTING 


Inasmuch  as  all  of  the  mines  of  this  district  are  of  moderate  daily 
output   and   therefore   do   not   require  uninterrupted   hoisting   at  high 


<38  COAL    MINING   INVESTIGATIONS 

speed,  the  hoisting  equipments  are  not  remarkable  in  any  respect.  The 
hoisting  shafts  are  all  timber  lined  and  of  moderate  size,  ranging  from 
a  single  compartment,  5  feet  by  8  feet,  to  double  compartment,  9  feet 
by  14  feet.  The  hoisting  engines  are  usually  16  inches  by  32  inches, 
only  two  of  the  mines  examined  having  24-inch  by  36-inch  engines. 
Cable  drums  are  of  ordinary  size,  varying  in  diameter  from  5  to  7  feet. 


Fig.  23.     Shale  and  top-soil  overlying  coal 

Many  of  the  mines  were  opened  before  the  perfection  of  automatic 
caging  and  at  none  of  the  mines  examined  was  automatic  caging  prac- 
ticed. This  district  played  an  important  part  in  the  development  of  the 
self-dumping  cage  and  all  of  the  larger  mines  use  this  type  of  cage. 
Table  16  gives  data  concerning  hoisting  equipment  for  each  mine 
examined. 

Fig.  19  shows  a  caging  place  typical  of  this  district. 


Table  16- 

—Equipmen 

t  for  Hoisting 

[No. 

Coal 

reached 
by- 

Aver. 

age 
daily 
ton- 
nage 

Hoisting  shaft 

Depth  1  Size 
in  feet  1  in  feet 

No. 
hoisting 
com- 
part- 
ments 

Self 
dump- 
ing cage 

Hoisting  engine 

Drum 

of 
mine 

Type 

Size  in 
inches 

Diameter 
in  feet 

Length 
in  feet 

91 
92 

Shaft.  . . . 

Shaft 

Shaft. . . . 
Shaft. . . . 
Slope  . . . 
Shaft.... 

1,250 
150 

2,600 

800 

50 

300 

217 
240 
186 
90 
SloDe 
223 

8  x  12 
7  xl2 

9  x  14 
6  x  14 

5x8 

2 
2 
2 
2 
1 

Yes 

No 

Yes.... 
..do... 
No.... 

Direct  connected. 
..do 

24x36 
16x32 
24x36 
16x32 

7 

Si 

7 
5 
5 
5 

2\ 
4 

93 
94 
95 

..do 

..do 

2\ 
2 

4 

97 

2 

Yes.... 

Direct  connected. 

16x32 

4 

MIXIXG    PRACTICE 


39 


PREPARATION  OF  COAL 

There  are  no  eoal  washeries  or  rescreening  plants  in  the  district 
and  all  sizing  is  done  over  gravity-bar  or  shaking  screens.  The  separa- 
tion into  sizes  goes  no  further  at  the  average  mine  than  to  divide  the 
output  into  coal  called  lump  that  will  go  over  bars  spaced  l1/^  inches 
apart  and  coal  called  screenings  that  will  go  through  these  bars.  The 
mines  of  largest  output  at  times  make  a  further  separation  dividing  the 
coal  which  goes  through  the  1 14-inch  screen  into  the  three  following 
sizes : 


Name 
Screenings 
Nut 
Slack 


Size 
Over  1  inch  and  under  iy±  inches 
Over  %  inch  and  under  1  inch 
Under  %  inch 


Fig.  24.    Steam-shovel  digging  sha 


A  very  small  per  cent  of  the  total  tonnage  of  the  mines  is  shipped 
as  run-of-mine;  the  largest  amount  at  any  mine  being  25  per  cenl  of  the 
output.  A  few  of  the  mines  makes  a  small  amount  of  3-inch  and  4-inch 
lump.  A  cleaner  separation  into  the  required  sizes  can  be  obtained  at 
several  mines  by  the  installation  of  a  longer  screen.  Table  K  gives  data 
concerning  tipple  equipment.  The  tipple-  of  the  district  are  all  of 
frame  construction. 


40 


COAL    MINING    INVESTIGATIONS 


As  stated  on  page  12  iron  pyrites  or  "sulphur"  occurs  more  plenti- 
fully in  bed  7  than  in  bed  6,  and  when  the  pyrites  is  not  disseminated 
through  the  coal  but  is  present  in  nodular  form,  it  can  easily  be  separ- 
ated from  the  coal  by  hand  at  the  working  face.  This  separation  serves- 
the  double  purpose  of  making  cleaner  coal  and  of  segregating  a  valuable 
by-product.  The  pyrites  thus  obtained  was  sufficient  in  quantity  at  two 
mines  working  in  No.  7  bed  to  warrant  the  erection  of  small  plants  for 
removing  the  coal  that  adheres  to  the  nodules  of  pyrites  before  the 
pyrites  is  shipped  to  a  sulphuric-acid  plant.  The  pyrites  with  adhering 
coal  is  crushed  to  lV->-inch  mesh  and  elevated  to  a  bin  whence  it  is  dis- 


Fig.  25.    Drilling  hole  for  blasting  at  stripping-mine 


charged  into  a  revolving  trommel  T  feet  long  and  3  feet  in  diameter  with 
2-inch  round  holes.  The  oversize  from  this  trommel  goes  to  a  one-cell 
jig  for  washing.  The  undersize  goes  to  a  second  trommel  with  ly^-inch 
perforations  and  the  undersize  from  the  second  trommel  is  discharged 
into  a  three-cell  jig  which  separates  coal  and  pyrites.  The  oversize  from 
the  second  trommel  and  the  undersize  from  the  first  trommel  are  ele- 
vated to  a  third  trommel  with  %-inch  perforations  from  which  the 
oversize  goes  to  market  and  the  undersize  to  the  three-cell  jig  which 
cleans  the  fine  pyrites. 


41 


Fig.  26.     Dinky  locomotive  and  haulage-way  at  stripping  mine 


Km;.  27.    Stripping  mine  haulage  way 


42 


COAL   MINING   INVESTIGATIONS 


The    surface    power    plants    of    this 
features  either  of  arrangement  or  size. 


plant.     The  total  horsepower  developed  at  any  mine  is 


district    present    no    unusual 
Fig.  2  shows  a  typical  surface 


not  large  and  on 


Fig.  28.    Stripping  mine  through-cut 

account  of  the  moderate  outputs  there  is  no  necessity  for  the  storage  of 
many  empty  cars  above  the  tipple.  Table  18  gives  data  on  surface  equip- 
ment for  each  mine  examined. 

Table  17 — Tipple  Equipment 


No. 

of 

mine 

Coal 
bed 

Screen 

Per  cent 

of  coal  over 

l\  inches 

Type 

• 

Length 
in 
feet 

Width 
in 
feet 

Inclination 
in  inches 
per  foot 

91 
92 
93 
94 
95 
97 

6 
6 
6 

7 

Bar 

Bar 

Bar 

Shaker  .  100  shakes  per  minute. 
Bar 



12 
24 
33 
22 
6 
36 

8 
8 
9 
6 
4 
8 

4 
4| 

4 
4 
4 
4 

40 
70 
65 
60 
55 
50 

Table  18 — Surface 

Equipment 

No. 

No. 
loading 
tracks 
under 
tipple 

No. 
empty 

cars 

possible 

to  store 

above 

tipple 

Boilers 

Electric  generators 

of 
mine 

No. 

Total 

Type            horse 

power 

Average 

steam 
pressure 

Manufacturer 

K.  W. 

Voltage 

91 
92 

2 
2 
4 
2 

60 
8 
57 
24 

2 
1 

6 
3 
1 

3 

Fire-tube  . . 
Fire-tube  . . 
Fire-tube  . . 
Fire-tube  . . 
Water-tube 
Fire-tube . . 

300 
90 

900 

450 
18 

310 

120 
125 
100 
100 
80 

Westinghouse. . . . 

10 

250 

93 
94 
95 

Westinghouse 

Western  Electric. 

150 
22i 

275 
250 

97 

4 

50 

43 


44  COAL    MINING    INVESTIGATIONS 


STRIPPING 


In  the  Danville  district  the  removal  of  overburden  from  coal  lying 
at  depths  of  20  to  30  feet  below  the  surface  has  been  practiced  for  a 
longer  time  and  more  extensively  than  it  has  in  any  other  district  in 
Illinois.  Beginning  in  1866  with  the  primitive  method  of  exposing  the 
coal  by  removing  a  very  shallow  overburden  by  means  of  scrapers 
dragged  by  horses  the  process  developed  slowly,  horse  scrapers  being 
replaced  about  1900  by  the  drag-line  steam-shovel,  shown  as  it  appears 
at  the  present  time  in  Fig.  20,  which,  in  turn,  was  replaced  by  the  revolv- 
ing steam-shovel  in  1910. 

The  methods  of  stripping  now  employed  in  the  district  differ  in  the 
path  which  the  shovel  follows  while  digging,  in  the  manner  in  which  the 
top  soil  is  removed  from  the  shale  overlying  the  coal,  and  in  the  disposal 
of  the  spoil.  In  one  method  the  shovel  makes  a  continuous  cut  about 
50  feet  wide  in  a  circle  around  the  area  to  be  stripped  and  the  coal 


Fig.  30.    Stripping  mine  spoil-bank 

exposed  behind  the  shovel  is  mined.  The  shovel  having  completed  the 
first  circle  begins  a  second  just  inside  the  first  and  continues  to  move 
in  circles  with  constantly  decreasing  diameters.  Fig.  21  shows  the 
island  of  overburden  around  which  the  shovel  travels  when  stripping  by 
this  method. 

In  the  second  method,  the  shovel  instead  of  traveling  in  a  circle, 
goes  forward  and  back  across  the  property  in  parallel  straight  lines,  a 
haulage-way  for  disposing  of  the  material  mined  being  maintained  at 
one  side  of  the  property. 

Where  the  shale  overlying  the  coal  is  to  be  used  for  the  manufacture 
of  brick  or  for  other  purposes  and  is  overlaid  by  top  soil,  the  soil  is  first 
removed  by  hvdraulicino-.     As  fast  as  the  coal  is  mined,  the  top  soil  for 


45 


46 


COAL    MINING    INVESTIGATIONS 


50  feet  from  the  edge  of  the  bank  of  the  cut  is  washed  off  into  the  pit 
left  by  the  removal  of  the  coal.  For  washing  off  the  top  soil  hydraulic 
monitors  under  a  pumping-head  are  used  as  shown  in  Fig.  22.  The 
amount  of  top  soil  washed  per  eight-hour  shift  varies  with  the  material 


Fig.  32.    Section  of  bed  No.  7 


removed;  in  tight  ground  100  cubic  yards  may  be  the  total  for  the  eight 
hours;  in  loose  ground  2,000  cubic  yards  may  be  washed  off.  Fig.  23 
shows  in  the  foreground  the  soil  already  washed  down  into  the  pit  and 
in  the  background  the  overburden  of  shale  and  soil  overlving  the  coal. 


MIXING    PRACTICE  47 

Tig.  24  shows  the  shovel  digging  the  shale  overburden  and  exposing  the 
coal  after  the  top  soil  has  been  washed  off.  Fig.  25  shows  the  method  of 
drilling  holes  for  blasting  the  coal.  In  blasting  stripped  coal,  holes  2% 
inches  in  diameter  are  drilled  12  feet  apart  at  a  distance  of  5  to  9  feet 
from  the  face.  The  average  charge  of  powder  is  1V2  pounds  per  hole, 
and  the  average  gain  per  25-pound  keg  of  powder  is  100  tons.  At  this 
stripping  mine  the  hauling  is  done  by  small  steam  locomotives  as  shown 
in  Fig.  2G. 

At  one  stripping  mine  in  the  district  the  steam-shovel  digs  a  perma- 
nent haulage-way  along  one  side  of  the  area  to  be  stripped  as  shown  in 
Fig.  27.  At  the  end  of  this  haulage  cut  a  thorough-cut  about  50  feet 
wide  is  made  along  the  boundary  of  the  property.  Fig.  27  shows  the 
branching  of  the  thorough-cut  from  the  haulage-way  and  Fig.  28  shows 
the  shovel  at  work  in  the  thorough-cut.  The  exposed  coal  is  mined 
behind  the  shovel  as  is  shown  in  Fig.  29.  When  the  thorough-cut 
reaches  the  property  line  the  shovel  turns  around  and  digs  the  over- 
burden from  another  strip  about  50  feet  wide  depositing  the  spoil  in  the 
pit  made  by  the  removal  of  the  coal  exposed  by  the  "thorough-cut." 
This  spoil  bank  is  shown  in  Fig.  30. 

Fig.  31  shows  a  steam-shovel  which  elevntes  the  spoil  by  a  belt- 
conveyor  and  deposits  it  along  the  side  of  the  shovel-cut. 

The  tipples  at  stripping  mines  are  usually  rough  housings  of 
shaking-screens  raised  sufficiently  above  the  railroad  tracks  to  allow 
dumping  into  cars  and  approached  by  a  steep  incline  up  which  the  pit 
cars  are  drawn  by  cable. 

Fig.  32  shows  a  section  of  coal  No.  7  in  this  district  and  also  shows 
the  shale  and  top  soil  overlying  the  coal.  The  total  cost  of  mining  coal 
by  stripping  the  overburden  varies  on  a  daily  output  of  300  tons  per  day 
from  40  to  50  cent-  per  ton  loaded  on  the  cars. 


PUBLICATIONS  OF  THE  ILLINOIS  COAL  MINING 
INVESTIGATIONS 


Bulletin  1.     Preliminary  Eeport  on  Organization  and  Method  of 
Investigations,  1913. 

Bulletin  2.     Coal  Mining  Practice  in  District  YIII    (Danville), 
by  S.  0.  Andros,  1914. 


